Thanks Keith, As I say, I was not sure what could be causing this and was more than willing to accept that running the new GUI and the slowdown occuring were simply a coincidence in that my MacBook was also starting to struggle in general. It's a good point about the Console logs though and I admit I am guilty of not doing that but will do in future. keithcurtis said: FWIW, I don't think it's either. I also run on Mac/Chrome and have just switched to the new UI. We ran our last game that way with no lag, running both audio and video through Roll20. No lag, overheating or fan. As an aside, I hope that everyone who reports lag or CPU spikes is also sending Console Logs ( Chrome , Firefox ) and Help Center Requests . It's the only way Roll20 has of gathering data on this problem which seemingly affects some consistently, and other not at all. The Aaron said: As a fellow Mac user, I had this same problem about a month ago. For me, when performance would tank, I'd see kernel_task start using 700-900% of CPU in Activity Monitor. After some digging, I found out that kernel_task takes over CPUs if the system starts to overheat, which is often caused by fan blockage when GPU is in heavy use. Roll20 is the only thing that uses my GPU for the most part, so I'd only see it when Roll20 was active. I took the back off my MacBook and cleaned a huge amount of dust and cat hair out of it, and it's been performing great since. Saul J. said: I had the same problem with my old Mac - the kernel_task started taking up huge amounts of CPU and the machine slowed down to a crawl whenever I was playing WoW and only WoW . In my case, it turned out to be a bad battery, that was triggering a problem on the motherboard (the motherboard had been replaced during the pandemic by a 3rd party since Apple stores weren't doing any repairs). The motherboard that the 3rd party put in turned out to be defective when I finally had it diagnosed by Apple. Needless to say I bought a new machine - at that point, since the machine was no longer under Apple Care (it was during the pandemic) the new motherboard would have cost me nearly 2/3 the cost of a new machine not counting the battery replacement so it was wiser to just upgrade machines. Anyway, what the OP should do (IMHO) is to open up Activity Monitor while playing Roll20 and see if kernel_task starts chewing up all the CPU. If that is really what is happening, that's certainly your lag problem. It means that there's a hardware problem somewhere on your machine. If you have any diagnostic tools available, you can run them but the easiest thing to do is to just go to the Genius Bar at a local store and have them run their diagnostics. It's free except for the cost of gas. :-) Their tools go much deeper in checking out the hardware than any other tool. If Roll20 is the only thing lagging, I'd guess the problem is somewhere in the GPU and the hardware acceleration is causing the problem. But it will take deep diagnostics to be certain. As a temporary solution, you can try to turn off hardware acceleration and see if the problem eases. It might not go away if it's the GPU that's bad but it might help. But, turning off the hardware acceleration might lead to other problems with Roll20. Again, the Apple diagnostics are your best bet to find out the real hardware issue. The Aaron said: EndoViper said: Before the redesign I did have some issues with slowdown from time to time and my Macbook fan was pretty much always at 100%, but this seemed to be magnified last night. The session had been running for around two hours and gradually each thing I tried to do seemed to be taking longer (so, opening map selection and moving between maps, opening character sheets, moving tokens and pinging). Also, the video feeds from the players were becoming more and more laggy with the video ending up running about five minutes behind the audio I was hearing on Discord and looking like it was in slow motion. By the time it came to combat, with three PC's and eight NPC's, it was pretty much unusable. I managed to get everyone into initiative order but there was so much of a delay between trying to perform any actions, or rolls or changing to different sheets that we ended up just giving in. As a fellow Mac user, I had this same problem about a month ago. For me, when performance would tank, I'd see kernel_task start using 700-900% of CPU in Activity Monitor. After some digging, I found out that kernel_task takes over CPUs if the system starts to overheat, which is often caused by fan blockage when GPU is in heavy use. Roll20 is the only thing that uses my GPU for the most part, so I'd only see it when Roll20 was active. I took the back off my MacBook and cleaned a huge amount of dust and cat hair out of it, and it's been performing great since. I have been watching Activity Monitor over the last day whilst in R20 preparing the next session...adding some pretty hefty maps with weather, music etc. and the kernel task CPU % has never gone above 3.5%...however, I do know that both Chrome and Discord can be CPU and RAM killers, so I am going to try and set up a test session with my players with a resource heavy map just to monitor the kernel task % more. I have also have a P5 screwdriver on it's way to me today so I can take the bottom of my Macbook off and give it a good clean out in case it's something as simple as dust build up causing overheating. It's done me well for five Years now but it's never actually used as a proper laptop anymore and is always docked on my desk so I am considering just getting an M2 Pro MacMini later this Year....just need the Macbook to hold out until then. Thanks for all the advise everyone though, and sorry for bringing this up in this thread as, like I say, I was not sure it had anything to do with the redesign.